[match/match.git] / program / ArrayStuff.hs

module ArrayStuff where
import Data.Ix
import Data.Array.IArray

funcArray lohi f = listArray lohi $ map f $ range lohi

constArray lohi v = listArray lohi $ repeat v

transposeArray arr =
	let swap (x, y) = (y, x) in
	let (lo, hi) = bounds arr in
	ixmap (swap lo, swap hi) swap arr

array2DtoListOfLists arr =
	let ((xlo, ylo), (xhi, yhi)) = bounds arr in
	map (\x -> map (\y -> arr ! (x, y)) $ range (ylo, yhi)) $ range (xlo, xhi)

listOfListsToArray2D ll =
	listArray ((0, 0), (length ll - 1, length (head ll) - 1)) $ concat ll

-- Use instead of amap when the array implementation needs to change.
-- E.g., mapping an unboxed array to an array whose elements must be boxed.
amap2 f arr = funcArray (bounds arr) (\i -> f (arr ! i))

-- Like amap2 but the mapping function is also passed the index.
aixmap f arr = funcArray (bounds arr) (\i -> f i (arr ! i))
Commit	Line	Data
967c39ef MM	1	module ArrayStuff where
	2	import Data.Ix
	3	import Data.Array.IArray
	4
	5	funcArray lohi f = listArray lohi $ map f $ range lohi
	6
fd0d2377 MM	7	constArray lohi v = listArray lohi $ repeat v
fd0d2377 MM	8
967c39ef MM	9	transposeArray arr =
	10	let swap (x, y) = (y, x) in
	11	let (lo, hi) = bounds arr in
	12	ixmap (swap lo, swap hi) swap arr
	13
	14	array2DtoListOfLists arr =
	15	let ((xlo, ylo), (xhi, yhi)) = bounds arr in
	16	map (\x -> map (\y -> arr ! (x, y)) $ range (ylo, yhi)) $ range (xlo, xhi)
	17
bbabbd01 MM	18	listOfListsToArray2D ll =
	19	listArray ((0, 0), (length ll - 1, length (head ll) - 1)) $ concat ll
	20
967c39ef MM	21	-- Use instead of amap when the array implementation needs to change.
	22	-- E.g., mapping an unboxed array to an array whose elements must be boxed.
	23	amap2 f arr = funcArray (bounds arr) (\i -> f (arr ! i))
eb6c3c9f MM	24
	25	-- Like amap2 but the mapping function is also passed the index.
	26	aixmap f arr = funcArray (bounds arr) (\i -> f i (arr ! i))